The invention concerns a cylinder head and an internal combustion engine having such a cylinder head.
Cylinder heads and internal combustion engines of the general kind set forth are already known from the state of the art. As from a given bore (about 150 mm) internal (gas) combustion engines are fitted with a pre-chamber for ignition boosting. An ignition source which projects into the pre-chamber ignites the mixture which is present there and which is relatively rich in the case of a flushed pre-chamber, whereby ignition flares pass from the pre-chamber into a main combustion chamber and ignite the mixture present there.
JP H 04171256 A discloses a valve comprising a valve body, a valve spring, a valve needle and a lower cavity which is supplied with gas. There is also an upper cavity in which the valve spring is arranged. Here a cap serves as a seal for the upper valve cavity, the cap being pulled over and screwed onto the upper cavity only thereby creating the upper cavity. The spark plug and the pre-chamber gas valve are arranged together in the same cavity. This can result in poor stability in smaller constructions.
DE 10 2004 000 229 A1 shows an injection system which injects gas on the one hand and Diesel fuel on the other. No common cavity for the spark plug and for the pre-chamber gas valve is shown.
There are various design concepts for supplying fuel to pre-chambers. In the case of non-flushed pre-chambers, in the compression stroke mixture is urged out of the main combustion chamber into the pre-chamber.
In the case of flushed pre-chambers there is also the possibility of an additional supply with fuel. That separate fuel supply can in turn be effected by way of passive valves (check valves) or active valves.
The packaging, that is to say the spatial arrangement of the components and supply lines which are required for a flushed pre-chamber concept, in the cylinder head, is demanding. To deal with the space problems there are approaches involving making the pre-chamber gas valves particularly small. That entails problems with service life as miniaturized pre-chamber gas valves are more susceptible to clogging or sticking of the moveable parts.
A further proposal in regard to the arrangement of the pre-chamber gas valve and the spark plug sleeve involves positioning the pre-chamber gas valve spaced relatively far from the pre-chamber, thereby giving a long passage from the pre-chamber gas valve to the mouth opening thereof into the pre-chamber. That can be disadvantageous for the reason that this gives rise to a large unflushed volume, a so-called dead space, which contributes markedly to soot formation in the pre-chamber gas combustion.